As is known in the art, field plate structures are used in some transistors to improve the efficiency of such transistors in many high power applications. One such field plate structure used with Field Effect Transistors (FETs) is a so-called source connected field plate (SCFP) structure having one end connected to the source, typically referenced to ground potential, through a SCFP connector section and a second end providing a SCFP region disposed over a region between the gate and the drain but separated or spaced from the drain. Two types of such source connected field plate structures are shown in: FIGS. 1A and 1B; and 2A and 2B, respectively; see for example U.S. Pat. Nos. 7,915,644 and 7,893,500, respectively. In both types, the SCFP structures include one end connected to the source through the SCFP connector section and a second end providing the SCFP region disposed over a region between the gate and the drain, it being noted that the end of the SCFP is spaced from the drain. That is, the two types of FETs differ in that with the type shown in FIGS. 1A and 1B the SCFP is connected to the source by a U-shaped SCFP connector section that does not pass over the semiconductor region, or active region, here for example, aluminum gallium arsenide (AlGaN) which may be a mesa on the substrate; whereas in the type shown in FIGS. 2A and 2B the SCFP structure is connected to the source by a SCFP connector section that does pass, as a canopy, over the semiconductor (or active region). With either type there is a continuous, solid dielectric structure of the same material that extends from the terminating end of the SCPF structure and the drain. Here, the FETs are adapted for use in high power, microwave frequency applications; here GaN FETs having a GaN buffer with an AlGaN semiconductor layer (sometimes referred to as the active region) as shown in FIGS. 1A, 1B and 2A and 2B.